1. Field of the Invention
The present invention relates to seeding devices. More particularly, the present invention provides a novel seeder of the type having a reciprocating seed pick-up needle and pressurized seed delivery.
2. Description of the Prior Art
Man's quest to provide himself and his family with food has long tested his inventive genius. Early agricultural techniques, involving broadcast sewing of seed and hand tilling of soil, have given way to mechanized seeding and tilling.
The field of mechanical seeding has been quite fertile for innovation. Early mechanical seeding techniques, such as the use of a seed drill, have ripened into many different known automatic, mechanical seeding devices. One such device is the "Single Seed Selector and Planter" of Giannini, U.S. Pat. No. 3,380,626, issued Apr. 30, 1968. Operation of such device, as best seen in FIG. 6 of the patent, uses a series of hollow, spoke-like projections radiating from a hub and rotated thereabout. The projections pass through a seed bed wherein a pressure differential allows them to lift a seed from the seed bed and carry it upwardly. A blast of air at a seed delivery location blows the seed from the projection and into a seed delivery system.
A similar rotary seed delivery system is the "Pneumatic Seed Dispenser" of Beebe, U.S. Pat. No. 3,788,518, issued Jan. 29, 1974. FIG. 2 of the patent shows a plurality of pipe-shaped projections, radiating from a central hub. The projections are rotated through a circuit in a manner similar to that shown in the Giannini patent. Beebe also includes a valve for removing the pressure differential on the projection at selected points along its rotary circuit, such that the seed is allowed to fall from the projection for delivery to a seed port.
Giannini and Beebe are typical of most modern automatic seeding devices. Such devices use a rotary pick-up device having a plurality of projections which radiate from a central hub and which are moved through a rotary circuit that includes a seed bed and a delivery port. Such devices are designed for delivering a serial flow of individual seeds, such as in the tractor drawn seeder shown in both patents.
Typical rotary seeders, are very complicated mechanically. Rotary motion of a seed pick-up projection through a seed bed and delivery circuit, while controlling a pick-up pressure differential, requires the coordinated interaction of many moving machine parts. The more complicated a machine, the more likely there will be mechanical failure of the machine. This is especially true when taking into account the brutal environment in which these machines are typically operated. The cogs, gears, wheels, and chains that operate rotary seeders are susceptible to damage due to accumulation of dirt and field debris. The result is that such machines require frequent maintenance.
An additional shortcoming of rotary seeders is that sweeping a projection through a seed bed does not produce a positive pick-up action for precision seed engagement with the projection. Oftentimes the projection will miss and not pick up a seed. Failure to pick up a seed reduces seed delivery and thereby reduces crop yield.
The sweeping motion of the rotary seeders also requires a large supply of seed in the seed bed--at least enough to totally surround the projection as it passes through the seed bed. As a result, a rather large seed hopper, containing excess seed (which is to say, wasted seed), must be included with such devices.
Rotary seeders are useful when seeding a field; in a greenhouse environment, they have significant drawbacks. For example, a rotary seeder may be ganged such that an entire row in a planter flat may be filled simultaneously. It is not practical--due to the mechanical complexity of such devices--to fill an entire flat at one time. There is no practical way to use a rotary seeder for precision seed delivery in a greenhouse setting.
Improvements in agricultural efficiency often come slowly. The rotary seeder produced an improvement in agricultural productivity. There are further gains to be made. Improving seeder reliability and simplicity, while increasing the precision with which seeds are delivered would be another significant step in improving agricultural productivity.